Method and apparatus for splicing a standby web to a running web

ABSTRACT

Disclosed herein is a method for splicing the leading end of a standby web to a running expiring web, rotatably supported on an unwind means, comprising the steps of: providing a running web storage means for maintaining, at a substantially constant value, the speed at which the running web leaves the web storage means when the speed of the running web entering the web storage means changes; restraining the running web with a web guide means; applying a braking force to the web guide means so that the tension in the running web between the web guide means and the unwind means is almost zero; sensing the end of the running web with a web tail sensing means, after it has become disengaged from the unwind means; stopping the running web by grasping the running web with a clamp means, after the tail end of the running web has passed through the web tail sensing means; effecting a splice between the leading edge of the standby web and the running web, while both webs are stationary; and severing the running web. An apparatus for accomplishing the above method is also disclosed.

United States Patent n 1 Shearon et al.

1 1 June 24, 1975 1 METHOD AND APPARATUS FOR SPLICING A STANDBY WEB TO A RUNNING WEB 175] Inventors: Michael Hillas Shearon, Newark.

Del; Roland Leroy Besel, Lugoff. S.C.

[73] Assignee: E. l. du Pont de Nemours & Company, Wilmington, Del.

1221 Filed: July 13.1973

211 App|.No.:378,968

[52] US. Cl 242/581; 156/504 {51] Int. Cl B65h 19/18 [58] Field of Search 242/581 58.3, 58.4. 58.5,

[56] References Cited UNITED STATES PATENTS 2.987.108 6/1961 Kilmartin 242/581 X 3.024.157 3/1962 Beerli r 242/581 X 3.634.171) 1/1972 Hottcndorf l 156/502 X 3.645.463 2/1972 Helm 242/581 3.728.197 4/1973 Harris et a1. 24258.4

Primary E.raminer]0hn W. Huckert Assistant lEImminer-John M. Jillions 57 ABSTRACT Disclosed herein is a method for splicing the leading end of a standby web to a running expiring web. rotatably supported on an unwind means. comprising the steps of: providing a running web storage means for maintaining. at a substantially constant value. the speed at which the running web leaves the web storage means when the speed of the running web entering the web storage means changes; restraining the running web with a web guide means; applying a braking force to the web guide means so that the tension in the running web between the web guide means and the an wind means is almost zero; sensing the end of the running web with a web tail sensing means. after it has become disengaged from the unwind means; stopping the running web by grasping the running web with a clamp means. after the tail end of the running web has passed through the web tail sensing means; effecting a splice between the leading edge of the standby web and the running web. while both webs are stationary; and severing the running web An apparatus for accomplishing the above method is also disclosed.

13 Claims, 9 Drawing Figures SHEET PATENTED Jun 24 I975 PATENTEDJuu24 m5 3 8 158 SHEEI 3 PATENTEDJUN 24 ms SHEET PATENTEDJUNZ4IQTS SHEET lja Ca/MM PATENTEDJUN24|915 F l G- SHEET METHOD AND APPARATUS FOR SPLICING A STANDBY WEB TO A RUNNING WEB BACKGROUND OF THE INVENTION 1. Field of the Invention:

This invention relates to an apparatus and a process for unwinding web-form material of high intrinsic value, and for splicing a new roll of web to an expired roll with a minimum of waste. In particular, it relates to a plural position unwind apparatus in which wound rolls of web are brought to a stop for effectuating a splice. and to a downstream web storage festoon apparatus adapted to feed web, at full speed, to yet another downstream device, without interruption, while the splice is being effected. It relates further to an apparatus and method for controlling the operations incident to web storage, stopping, splicing, cutting and restarting forward motion of the web.

2. Background of the Invention:

There are three criteria applied to any process for automatically splicing the leading end ofa standby web to a running web. The first of these is speed. The use of extensive shut-down time, to splice webs in a commercial plant, is an expensive proposition. The second is waste. With webs of high intrinsic value, the automatic splicing operation cannot leave a considerable amount of extra web on the core after the splice and cutting operation has been accomplished. Depending upon the value of the web, and the number of splices being made, anything more than a few feet of web may be considered to be a considerable amount of web. Finally, the operation should be accomplished as smoothly as possible. Often the running web is being fed to a downstream processing unit, and the effectiveness of that unit will depend on the amount of tension in the web, or at least upon the variation in tension in the web. The web splice should. therefore, be accomplished with a minimum amount of change in the tension in the running web as it enters any downstream processing unit.

In prior art splicing devices, reliance has been placed on measuring the diameter of the expiring roll to detect imminent exhaustion of the web on the roll. When this state is sensed, other operations, such as unwind stopping or unwind deceleration without stopping, followed by splicing, web cutting and the like are initiated. Since web cores are usually employed in the unwind, and since these web cores usually have diameters which vary from roll to roll, the diameter sensing device must be adjusted to initiate the stopping or decelerating of the roll, based on the diameter of the largest of these cores (plus a heel of web). The result is that, when a small diameter core is encountered, the machine cannot compensate for the difference in diameter, and the diameter sensing device initiates the splicing operation when a significant amount of web is left on the core.

Alternate attempts to splice the leading end of a standby web to the tail end of the running web, after the tail of the running web has left the core, have not been contemplated because the tail end of a web has, heretofore, been considered to be uncontrollable after it falls free of the unwind core.

Those splicing techniques which attempt to splice the leading end of a standby web to a running web, without stopping the running web, are generally unreliable. They may be fast, but they either leave a considerable amount of web on the roll. or, in an attempt to utilize as much web as possible, the tail end of the web flies free, and the whole process has to be stopped. Those splicing techniques which depend on rapid deceleration of the unwind roll also have problems. Because of the insensitivity of the diameter sensing devices used, these techniques also leave a considerable amount of web on the roll. Furthermore, the rapid deceleration. and particularly the stopping of the unwind roll used in such techniques. can cause excessive variations in the tension of the running web.

The present invention is directed to a method and ap paratus for effecting a splice between the leading end of the standby web and a running web, as rapidly as possible. without causing undue fluctuation in the tension of the running web. and without leaving a significant amount of running web on the web core after the splice is effected. The present invention avoids the use of a diameter sensing device as a means for initiating splicing operations on the web. It proceeds to effect :1 splice in a short period of time (e.g., 15 seconds) while maintaining a continuous, constant, and high speed flow of web (e.g., 400 fpm or more) to a web consuming device. It accomplishes this with a minimum of waste, a high degree of reliability, and a minimum of edge misalignment. This last fact is often of great importance.

The present invention utilizes a web guide means, positioned between the unwind means and the splicer, to restrain the web and a braking means to apply a braking force to the running web between the web guide means and the unwind means so that the tension in the running web between the web guide means and the unwind means is almost zero. It proceeds by allowing the tail end of the web to pull free of the web core, and uses the tail end of the running web, to initiate running roll web stoppage and splicing operations. Complete control over the expiring web end is maintained up to and even after the splicing and severing operation have been effected.

SUMMARY OF THE INVENTION The above objects are accomplished by providing a method for splicing the leading edge of a standby web to a running expiring web rotatably supported on an unwind means comprising the steps of:

a. providing a running web storage means for maintaining, at a substantially constant value, the speed at which the running web leaves the web storage means when the speed of the running web entering the web storage means changes;

b, restraining the running web with a web guide means;

c. applying a braking force to the web guide means so that the tension in the running web between the web guide means and the unwind means is almost zero;

d. sensing the end of the running web with a web tail sensing means, after it has become disengaged from the unwind means;

e. stopping the running web and by grasping the running web with a clamp means, after the tail end of the running web has passed through the web tail sensing means;

f. effecting a splice between the leading end of the standby web and the running web and, while both webs are stationary; and

g. severing the running web.

This method is accomplished by providing an appara tus of the type comprising. unwind means for supporting a roll ol running. expiring web; means for supporting a standby web roll; means to splice the leading end of the standby web to the running web and severing the running web; driving means for the running web; running web storage means; and first speed control means to maintain the speed at which the running web enters the storage means at a first predetermined high speed: the improvement residing in the use of a running web control device comprising:

a. web guide means. positioned between said unwind means and said means to splice. to coact with the run ning web and to restrain the tail of the running web when it becomes disengaged from the unwind means so that the running web is fed evenly to the means to splice;

b. web guide braking means to apply a braking force to said web guide means so that the tension in the running web between the web guide means and the unwind means is almost zero;

c. web clamp means; and

d. web tail sensing means for sensing the end of the running web after it has become disengaged from said unwind means. activating said web clamp to grasp said running web and bring the running web to a stop. and energizing said means to splice when the running web has stopped.

In the preferred embodiment. the apparatus further comprises an unwind braking means for applying a braking force to the unwind means; and a second running web control means. responsive to the quantity of running web on the roll. for actuating the unwind braking means and decelerating the unwind means to the point where the running web enters the storage means at a second predetermined low speed. when the quantity of running web on the roll of running web approaches a predetermined quantity.

In this embodiment. the braking force applied by the unwind braking means to the unwind means is closely matched by the braking force applied to the web guide braking means so that the tension in the web between the web guide means and the unwind means is almost. but not quite. zero. The second running web control means then controls the speed at which the running web enters the storage means. after it has been decelerated to its second predetermined low value. by applying a variable braking force to the web unwind means, using the unwind braking means. and a fixed braking force to each of the web guide rolls. The main reason for decelerating the running web from its high speed to the low speed is to allow accurate web edge alignment. Once the tail end of the running web has broken loose from the unwind means and the clamp has been applied to stop the web. there is no accurate way to control the web edge alignment. Variations in web edge alignment are decreased if the web is first slowed to a low speed.

In a more preferred embodiment. the web guide means comprises at least two web guide rolls. and the web tail sensing means is located between the guide rolls. The web clamp is located between the splicer and the web guide roll closest to the splicer. and both web guide rolls are free running vacuum rolls adapted to restrain the running web by means of a vacuum holddown. This vacuum holddown prevents the tail end of the running web from uncontrolled motion. while still allowing the tail end to initiate the splicing action by passing through are b Is ing means The action of the apparatus is such that the running web is stopped. and the splicing operation is effectuated he fore the tail of the running web has time to travel from the web tail sensing means to the second guide roll.

After the web tail end has passed through the web tail sensing means. it is possible to bring the running web to a rapid halt by firmly gripping the web tall with the web clamp. It is preferable. however. to employ a web clamp which will allow the web to slip a certain dis tance before stopping This gradual stop decreases the tension variations which occur downstream of the web storage device.

If it is possible to provide a very large web storage device. timing in the present invention is not necessarily critical. Under normal circumstances. however. it is difficult or at least undesirable to provide a web storage device with more than a hundred feet ofcapacity. With the running web traveling at speeds at excess of 400 fpm. this means that the entire operation. from the first deceleration of the unwind means. to the point where the standby roll reaches maximum acceleration. must take place in about 15 seconds. This means that there must be a rapid transition between the normal. high speed. state of the running web. and the intermediate low speed state of the running web. In this context. it has been found that the use of two brakes. one associated with the unwind mechanism. and the other associ ated with the web guide rolls will provide the desired change. The conventional pneumatic disc brake associated with the unwind means will decelerate the unwind means to the desired low speed. and then when the pneumatic pressure is relieved. the constant speed level. which can be controlled by the second speed con trol means. is established almost instantaneously.

BREIF DESCRIPTION OF THE DRAWINGS The present invention. can invention be described with reference to the following figures. in which:

FIG. I is an elevational view of one embodiment of the unwind-splicer of the present invention. shown feeding web to a festoon type storage device;

FIG. 2 is an isometric view of the unwind unit of FIG.

FIG. 3 is an isometric view of part of a dancer control mechanism useful in a fcstoon web storage device. both similar to devices taught by Butler in US. Pat. No. 3.414.208;

FIG. 4 is a plan view of a splicer useful in the present invention;

FIG. 5 is a sectional view taken on line 5-5, FIG. 4;

FIG. 6 is an isometric view of one feed roll and web clamping arrangement useful in the present invention;

FIG. 7 is a diagram of pneumatic circuits useful in the present invention;

FIG. 8a is an electrical diagram showing one portion of the controls used with the apparatus of FIGS. I6; and

FIG. 8b is an electrical diagram showing another portion of the controls used with the apparatus of FIGS. [-6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The conventional features of the web supply apparatus ofthe present invention comprise: an unwind means B for supporting a roll 97 of running web C; means A for supporting a roll 97' of standby web C; means D for splicing the leading edge of the standby web to the running web, and severing the running web; drive means E for the running web; and running web storage means F. Normally some speed control means to main tain the speed at which the running web D is supplied to the storage means F is included. In the apparatus shown in FIG. I. this speed control means (referred to herein as the first speed control means) is incorporated into the running web control device and will be described in conjunction with that device.

Starting from the left-hand side of FIG. I, running web C is advanced at a constant velocity in its lengthwise direction by means of some driving means E locatcd downstream of the web storage device F. This driving means is illustrated by a vacuum roll drive com prising a hollow vacuum roll driven by a motor 27.

RUNNING WEB STORAGE DEVICE The running web storage device F illustrated in FIG. I is a festoon type web storage device of the type taught by Butler ct al. in US. Pat. No. 3.414.208, the disclosure of which is hereby specifically incorporated into this disclosure. In general such a web storage device comprises a number of fixed web guide rolls. and a number of movable web guide rolls on a dancer assembly 80. The device is designed to store a sufficient length of web-forming materials so that the web can be supplied uninterruptedly. and at a constant velocity, to a downstream web consuming apparatus, during a time period in which the web fed to the storage apparatus is slowed or completely stopped. Typically, this stoppage occurs when a new web roll is spliced-in to replace an expiring roll of running webv In the web storage device shown in FIG. I, a triple roll configuration is employed. The apparatus comprises three sets of vertically aligned dancer rolls (upper rolls) cooperated with three sets of vertically aligned idler rolls (lower rolls). The dancer assembly 80 comprises outboard dancer rolls 386a, 386b, 388a. 388b, 3900. and 390b; intermediate dancer rolls 394, 396 and 308; and inboard dancer rolls 402, 404 and 406. The inboard and outboard dancer rolls are similar in diameter than the intermediate rolls. All of the dancer rolls are of thin walled tubular construction and are mounted. at their respective ends. on bearings which are in turn mounted on a pair of yoke plates 72 and 74. only one of which is shown. These yoke plates are guided to move vertically on rails 446, only one of which is shown, by means of ball bearing rollers 94 which are supported by individual studs 96, secured to yoke plates 74. The rails 446 are secured to a frame 28.

The idler roll assembly comprises: outboard idler rolls 410a, 410b, 4120. 4l2h, 4141:. 4141). 444a. and 444). intermediate idler rolls 4I8, 420, 422, and 442; and inboard idler rolls 426, 428, and 430. All of these idler rolls are mounted at their respective ends on ball bearings which are in turn mounted on fixed shafts supported by frame plates 22. only one of which is shown. The frame plates 22 are integral parts of frame 28.

Dancer assembly 80 is moved upward (ie, away from the idler rolls) by means of the mechanism shown in FIGS. I and 3. and described in US. Pat. No. 3.414.208 [specifically at column 4, lines 7-49). For convenience. a portion of this disclosure is included hereinv The mechanism for raising the dancer assembly 80 upward includes a pair of endless roller chains 104.

only one of which is shown. each arranged to form a closed loop and each coupled. respectively. to yoke plates 72 and 74. Both chains I04 are similarly arranged so that only the disposition of one of them will be described in detail. Chain I04 is connected at its ends to an anchor block I08 secured to the inside of the yoke plate 74 to form a close loop guided by lower idler sprockets I10 and 112 and upper idler sprockets II4. Chain I04 is trained over a large drive sprocket I16 and meshes with a switch control sprocket II8. which is keyed to a short shaft I20 journaled in a side plate 20. Sprocket H6 is also keyed to a transverse shaft I22 which is journaled near its ends in the side plates 22.

The necessary force to urge dancer assembly upward is provided by a pair of piston assemblies. only one of which is shown. The piston assembly comprises a piston I24 securely mounted on rod I32. and slideably mounted in cylinder I28. A roller chain I36. con nected to rod 132. is wrapped about sprocket I38 which is keyed to shaft I22. In operation. when piston I24 is pressed downward under air pressure. shaft 122 and sprocket II6 are caused to rotate in a clockwise direction and. through the coupling provided to yoke plate 74 by the chain 104, dancer assembly is urged upward so that a greater quantity of web can be stored. The relative pitch diameters of sprockets I38 and II6 are chosen so that the stroke of piston 124 will allow the dancer assembly to travel from its lowermost position to a fully loaded position, somewhat higher than that shown in FIG. I.

A number of control devices. useful in the present invention. are associated with the web storage apparatus and its dancer drive mechanism. These control devices are described primarily with reference to FIG. 3. Shafts I20 and 122 are both extended through their respective bearings. outwardly of frame side plate 20. Shaft I22, which turns when the dancer assembly 80 is moved. carries plate cams and I46. Cam I40 engages follower roll 142 of a commercial pneumatic pressure regulating valve I44, which is secured to side plate 20 by means of a bracket 152. The rising portion of cam I40 is in timed relationship with shafts I22, sprocket H6 and chain 104. Through them it is also in timed relationship with dancer assembly 80 such that when the dancer. moving upward (i.e.. storing more web). reaches about the two-thirds point of its total al Iowable travel. cam I40 drives plunger 298 of valve I44 downward and maintains it in this condition for the entire remaining upper one'third travel of the dancer. For the upper one-third travel of the dancer assembly, this has the effect of increasing the output pressure of valve I44 above the output pressure that prevailed in the lower two-thirds of dancer travel. Cam I46 engages roller 148 of a normally closed limit switch I50, which is supported on plate 20 by means of bracket I54. Cam I46 is also timed relative to the dancer. so that switch I50 is closed" for the lower two-thirds, and opcn" for the upper one-third of the travel of the dancer. The circuit connections and the functions of switch 150 will be further described below.

Associated with shaft 120 is a device for sensing when web input to the festoon exceeds web output to a web consuming device. eg. a condition in which the dancer assembly is rising. This sensing device generally comprises a normally open switch I60 with an actuating arm I62 which causes the switch to close when the distal end of the arm is moved downward. This is accomplished by means of a gear 164. the teeth of which engage the end of arm I62. A stud I68 supports gear I64 which is driven by means of a gear I66. fixed to shaft 120. Gear I66 is, in turn. driven by means of sprockets H8. whenever the dancer assembly 80 is moved. Countercloekwise rotation of pinion I64, which occurs when the dancer assembly 80 rises. will close switch I60 each time a tooth of pinion I64 engages arm I62. Clockwise rotation of the pinion (i.e., dancer descending) on the other hand, has no effect on switch I60. The effect of the foregoing is that. when the dancer is rising, electrical pulses are produced in a cir cuit which will be described below. If desired, this ap paratus may produce a different number of pulses for a given amount of vertical motion of the dancer. by changing the number of teeth in either or both of gears I66 and 164.

Referring to FIG. I, a pair of web-guiding idler rolls (upper roll 37 and lower roll 39) are situated on the end of the web storage apparatus, facing toward the unwind. The lower roll 39 comprises a thin hollow shell mounted by means of ball hearings on a fixed shaft, which is supported by frame 28. The upper roll 37 is keyed to shaft 41, so both rotate. Directly above roll 37 is a DC. tachometer 43 and a Dynapar* pulse generator 45, both of which are secured to frame 28. The tachometer 43 is driven, by a toothed belt and toothed pulleys, from the shaft 41 in a 2:1 ratio, so that the tachometer runs twice as fast as roll 37. The pulse generator 45 is, likewise, driven positively from the shaft 41, except in a 1:] ratio. In the embodiment illustrated, the pulse generator 45 is adapted to emit 314 electrical pulses per inch advance of the web traveling over idler roll 37 (neglecting slippage). The outputs of the DC. tachometer 43 and the pulse generator 45 are used in separate devices and circuits to be described below. Trademark of thc Dynapar Division. Litton Industries SPLICE-UNWIND UNIT Referring to FIGS. I and 2, the splice-unwind unit generally comprises: a frame SI, supported on a sub frame 49 which is recessed in the floor; and a vacuum rollsplicer unit 53. On opposite sides of the splicer unit are ways 55a and 55b. for supporting unwind unit B and standby web unit A. Naturally, when the running web has expired. and a splice has been made, the functions of these two stations are reversed. For eovenience, both of these units will. therefore, be referred to as unwind units. Within the lower portion of the sub frame 49 are idler rolls 57 and 59 which serve to guide the web from the unwind-slicer to the first idler roll 39 on the web storage device.

The A and B unwind units are substantially identical, so only one, the B or right-hand unit will be described. Referring to FIGS. I and 2, the unwind B generally comprises a base 6] movably mounted on ways 55b. Posts 63 and 65 support frame 69, at one side. by means of a pivot shaft 67. .Iournaled in flanged pillow blocks 7] on frame 69 is a reel shaft 73, which is adapted to carry a reel (not shown in FIG. 2) of webform material. The end of frame 69, opposite pivot shaft 67, is supported by a clevis mounted by hydraulic elevating cylinder 75; the rod end 76 of which is joined to frame 69 by pin 78.

Shaft 73 is provided with a screwed nut 77 to retain a reel of web. The opposite end of the shaft has, keyed thereto. a thin brake disc 8]. Associated with this brake disc is a pneumatically actuated caliper 83. composed of: a C-shaped frame 85. which is rigidly supported on the frame 69; and a pneumatic cylinder 87. which is adapted to squeeze individual brake shoes 79a and 79h against opposite sides of the brake disc 8], thereby ap plying a braking torque to the disc 8| and to the reel shaft 73.

Situated within frame 69 is an electrical pulse gcnerating device 89 which in the present embodiment is a Dynapar pulse generator; the functioning of this unit will be further described below. The device 89 is driven from shaft 73 in a I:l ratio, by means of a pair of gears 91, and emits one electrical pulse per revolution.

Within the sub frame 49 of each unwind is a foot mounted horizontal hydraulic cylinder 93, having its head end secured to the rear member of the main sub frame 49, and its rod end 93a connected to base 6]. This cylinder is adapted to drive base 6]. and all parts carried by it, back and forth on ways 55!) in a direction parallel to the axis of shaft 73. This is done to permit loading of reels and to permit adjustment or alignment of the web edge relative to other parts of the equipment. In this latter connection, bracket 95, which is secured to the top of the frame 69, is used to transmit the aligning motion to other members of the splicing device. as will be described.

Both cylinders and 93 have their fluid ports connected, by means of suitable conduits. to valves and to a suitable source of hydraulic fluid under pressure. The head end of the unwind elevating cylinder 75 is connected to a manual three-way valve (not shown) and thence to the hydraulic supply; the rod end is open to the atmosphere. The cylinder 93 is piped at both ends and connected via solenoid actuated valves SV42 and SV52 to a source of hydraulic fluid. The piston is driven by a differential in pressure applied to the re spective ends of the cylinder by activating one or the other of the solenoid valves. When both solenoids are nonactivated, the piston is locked in position.

Referring to FIG. I and FIG. 6, a vacuum roll stand I3I is rigidly mounted on frame 5I in a position central between unwind stands A and B. Vacuum roll stand 13], generally comprises a wcldment made up of rear posts [07a and 107b, center posts I09a and I09h. and a single front post III, all joined at their upper ends at longitudinal beams II3 and IIS, and at right angles thereto by transverse beams II7 and 119. The upper surfaces of these beams lie in a common horizontal plane and are adapted to support a splicer I21. In addition to the splicer. stand l3I carries a cantilevered upper vacuum roll 133 and a cantilevered lower vacuum roll I35 on both the A" side of the machine and the B" side. The upper vacuum rolls I33u and I331: are spaced farther apart than the lower ones 135a and I35b. The four rolls are substantially identical in design. thus only one will be described. Roll 133 comprises a hollow shell, which is pervious to air is rotatably supported at each end by commercial ball bearings. The inner races of these bearings are supported on a hollow shaft I37, which is nonrotatably mounted in ball bushings 127. This permits free axial motion of the shaft and thus of the roll I33.

The ball bushings are supported in brackets I25. Upper brackets I25 are bolted to vertical plates I23 and welded on the ends of the longitudinal beams I13 and I IS. Lower brackets are bolted to the sides of posts I07 and I09. The interior of the roll is a vacuum chamber. Vacuum applied to the rear end of the hollow shaft I37 will be communicated to the vacuum chamber and. through pores in the roll. to the surface of the roll. This vacuum can be used to draw the web against the roll.

Referring to FIG. 6, secured to each of shafts 137 is an arm I39, located between ball bushings I27. Behind each arm is a coil spring 14] which surrounds each shaft 137 and seats against the fixed part of each rear ball bushing. Coil spring MI urges shaft I37 and the vacuum rolls 133 and I35 *forward until a stop collar (not shown) on the shaft reaches a fixed abutment. The pairs of arms on one side of the machine, e.g., the A side, are generally angled and located so that they over lap each other, and are bolted together, by bolts 129, at about the midpoint between the shafts. The front face (or near side as viewed in FIG. 6) of joined arms I39 is directly in the path of the upper end of the bracket 95 on the unwind stand, when the unwind is moved along ways 55a and 55b by means of cylinder 93. It should be realized, however, that bracket 95 actually abuts the front face of arms 139 only when the unwind is in about the rearmost 2 inches of its travel. Thus. within that short transverse distance, the vacuum rolls will track or follow any transverse motions of the unwind, forward and rearward. This capability is used to automatically align the web.

Referring to FIG. 6, a hysteresis brake 143 is located at the back end of each vacuum roll 133a, 133b, 135a and 13517. This brake is a commercial unit made by Magtrol, Inc., and is used to apply a breaking torque to the web guide means. This brake generally comprises a reticulated pole structure comprising a stator, with a permeable body, having an annular gap. This gap is partly occupied by the wall ofa cup-shaped permanent magnet rotor mounted on the shaft, the axis of which is concentric with the central axis of the annular gap. The brake further comprises a 6V.D.C. coil means on the stator for producing a flux across the gap. Each brake 143 is secured to an arm which is fixed to its respective shaft 137. The shaft of each brake unit carries a gear 145 which is in mesh with a gear 147, secured to the rear of the respective vacuum rolls 133, and 135. Thus, when the brake coil means is energized. the braking torque cxerted on the cup is transmitted to the shaft of the hysteresis brake unit and thence directly to the vacuum roll shell.

Situated near the center of splicer stand [31 is a web clamp I49 shown, on the B side, in standby position, and, on the A side, in web-clamping position. Each clamp comprises a shaft I51 journaled in bearings secured to the posts, and driven by a rack I53 and pinion 155. The rack is joined to the rod of a pneumatic cylinder I57, which in turn is fastened to beam 115. A pair of arms I59, carrying a crossbar and a resilient pad 161 (e.g.. polyurethane rubber) are rigidly joined to shaft for rotation therewith. In the standby position, the arms are essentially vertical, as shown in the B side. Small beams I63 are mounted (by means of bolts 167) as cantilevers from the rear and center posts I07 and 109, parallel with shafts 151. These beams I63 carry resilient pads 165, which serve as abutment surface for the web, and pads 161 which contact the web when the web clamp is in clamping position.

In the clamping position, shaft 151 is rotated about 70 from the standby position. Web clamp pads I6! and I65 have lengths coextensive with the working faces, or axial lengths, of vacuum rolls I33 and [35.

Referring to FIG. I, on each side of pad 131, located between the lower vacuum rolls I35 and the splicer I2], is a web edge detector 169. One suitable web edge detector is detector model 40Gb manufactured by General Web Dynamics, Rockford, Illinois. This detector is a C shaped unit mounted on the machine frame so that the open portion of the C straddle the web edge The detector is composed of a pair of spaced. axially aligned tubes or conduits which are situated with their common central axis substantially in alignment with the web edge, and generally perpendicular to the plane of the web. The web passes through the C-shaped unit between the open tube ends without touching cither of them. The conduits in the C-shaped unit are connected to a pneumatic system which supplies air to both conduits. When the web is centered so that it is partially blocking the two conduits, a normal pressure system prevails. When the web moves either further into the C-shaped unit or further out of the C-shaped unit, a change in pressure occurs which is sensed by this system and transmitted to a valve which operates the drive mechanism. By means of this feedback system, unwind units A and B are kept in lateral alignment with one another.

Referring to FIGS. 1 and 6, on each of side of vacuum roll stand 131 is a web tail detector 181, located proximately to the web path, beneath each ofthe upper vacuum roll 133a and 1331). Any suitable detector such as a pneumatic or a photoelectric device can be used. One suitable web tail detector is a pheumatic device comprising an air supply tube on one side of the web and, in axial alignment with this tube, a commercial diaphragm operated switch I83, on the opposite side of the web. On passage of the web tail between the source of fluid and the switch, which can be due to either web breakage or roll expiration, air from the supply tube enters the aperture of the switch and acts on its diaphragm, causing the normally open electric switch to close. This signal is used to activate a number of steps which will be described below.

Referring to FIG. I, a splicer unit 121 is situated on top of stand 13]. The splicer illustrated is one which is substantially the same as that described by Butler et al. in U.S. Pat. No. 3,305,l89, the disclosure of which is hereby specifically incorporated into this disclosure. This particular splicing device is constructed for fast, reliable operation. It is coupled to a web severing device in a way such that the length of overlapping web is limited to a minimum upon the formation of each splice. Splice forming device I2] comprises right-hand nip roll 230 and left-hand nip roll 232, eccentrically mounted on shafts 234 and 236, respectively. These shafts are journaled in plate 237 which is in turn secured to transverse beams 117 and 119. Each shaft is coupled to a cylinder 226 or 228 by eccentric pins 241 and 243. These cylinders are designed to impart the necessary eccentric rotational motion to shafts 234 and 236 so that the nip rolls 230 and 232 which are mounted on the shafts can be brought into contact with one another and held in a stationary position during the formation of a splice.

The mounting of rolls 230 and 232 with respect to shaft 234 and 236 is exactly the same. so only one will be described. Roll 230 is of a rubber sheath, metal shell construction. Interspersed between shaft 234 and roll 230 is a pair of spaced apart eccentric bushings 238. keyed to the shaft near the end of the roll. Surrounding each of the bushings 238 is a combined bearing and pneumatic seal 240. necessary because of the fact that the leading end of the ready web is held on the surface of the nip roll by vacuum before the formation of the splice. Each roll 230 and 233 is a dynamically balanced. perforated roll. containing a single row of holes as shown in 248. Hoses 244 and 246 are connected through appropriate valves to a vacuum pump for bolding the leading edge of the standby web by vacuum. against rolls 230 and 232 in position for splicing.

Eccentric pins 241 and 243. which can best be seen by reference to FIG. 4. are provided on the rear end of shafts 234 and 236 for the purpose of moving either one of these shafts bodily. while the other shaft remains stationary. For shafts 243 these connections include rod cylinder 226. the head end of which is clevis mounted to the machine frame. Similar connections are provided for shaft 236, and include pin 243 and cylinder 228. Cylinders 226 and 228 which are supported on the outside of plate 237, impart a rotary motion to shafts 234 and 236. respectively. These shafts, in turn. impart splicing motion to rolls 230 and 232 and web cutting motion to knives 262 and 264. Knife 262 is supported between the spaced ends of two arms 266. which are pinned to shaft 234. outside roll 230. Knife 264 is similarly supported between the piston ends of two arms 268 pinned to shaft 236.

A web preparation table 270 is mounted above each nip roll 230 and 232. Each web preparation table 270 is supported on a pair of hinged pins 276 and 278 which pass lossely through plates 237. Part of table 270 is hollow and perforations 286 are provided in both of its major surfaces. These perforations are in communication with a vacuum system. so that the web can be held on the surface of the table by a vacuum. The cutting of the leading edge of the web and its preparation either with a suitable adhesive or double-face tape is conveniently carried out on table 270.

Referring to FIG. 5, there is shown a splice ready to be formed between a running web, from unwind unit B. and a standby web. from standby roll A. As shown in FIG. 5. the running web passes over an idler roll 292, located immediately to the left of nip roll 232. A similar idler roll 294 is provided to the right of nip roll 230. As depicted in FIG. 5., web B is the depleting web, and lefthand table 270 has been employed as a support for the preparation of the standby web A. The leading edge of the standby web has been cut square and has received a coating of adhesive 296. The leading end of web A is supported on the nip roll 232, and the nip roll is angu- Iarly oriented to a predetermined position for the proper presentation of the standby web into contact with the running web. One way of insuring that the two rolls are in proper lateral alignment is to provide an arrow scribed on the nip rolls and plate 237. On roll 232 the leading edge of the standby web is supported by a vacuum reaching the web through perforations 248.

To form the splice. cylinder 226 is energized in a manner which will be more fully described with reference to the electrical diagrams. When cylinder 226 is energized. it rotates shaft 234 in a counterclockwise di' rection. as can be seen from FIG. 5. Roll 230 is thus shifted so that the running web B contacts the leading edge ofthe ready web A to form the splice. At the same Iltttt. blade 262 mow. tovards t web. pushing it into engagement with the slotted receiving means 245 and severing the web After a brief interval. just sufficient to insure the formation ofthe splice. cylinder 226 is decnergized and shaft 236 returns to the position de picted in FIG. 5.

While the web is unwinding from the left or A position of the unwind. a new web supply roll is mounted on the right or B position. and the leading edge of the new roll is prepared in the same manner as employed for the leading edge of the A roll. When a standby web in the right or B unwind position is to be adhered to a running web from the left or A unwind position. cylinder 228 is energized. turning shaft 236 to shift head roll 230 and thus bring a running web into contact with the cement at the leading edge of the B web. At the same time knife 264 is actuated to cut off the running web by driving it to and penetrating it into contact with slotted receiver 245. After the splice has been formed. cylinder 228 is deenergized. and shaft 234 returns to posi tion depicted in FIG. 5. To signal the machine circuits that a splice will be made. and to properly energize the splicer. a SPDT switch L536 is used. This switch is located at the rear end of the splicer. and is supported by plate 237. It is engaged by a lug on shaft 247. so that when the operator prepares a web end. and swings the slotted knife receiver 245 to the side opposite to the one formerly occupied, which he must do to gain access to the nip roll. switch L836 is activated. This manipulation of the slotted knife receiver 245 also results in the placing of the receiver on the proper side of the machine for the next splice cycle.

PNEUMATIC CIRCUITS Referring to FIG. 7, the pneumatic circuits generally comprise a conduit 249 connected to a source of pressure regulated air. supplied at about to 150 psig. The conduit 249 carries air to a number of branches. each of which will be described. It will be understood in viewing the pneumatic diagram. FIG. 7. that all of the solenoid valves are shown in their electrically deen ergized state. On the other hand. normal" operation requires certain of the valves (to be identified) to be energized and to remain so until some extraordinary event takes place.

In FIG. 7, branch 30) leads to a manually adjustable pressure regulating valve 260, which supplies dancer cylinders I28 and I30. and regulates the amount of force acting to store web in the storage festoon. Regulating valve 260 is of the self-venting type. by which is meant that if the downstream pressure exceeds the set point. air is vented (via regulator 260) to the atmosphere until downstream pressure equals the set point. From valve 260, air is supplied to the cylinders. via a check valve 261. which is connected in parallel with a manually adjustable restriction valve 263. This restriction valve limits the outward flow of air (left. in FIG. 7) when the rods of the cylinders I28 and I30 are rising. i.e.. when the dancer is descending (or web output exceeds web input). In parallel with check valve 26] and restriction valve 263 is a second manually adjustable restriction valve 265 which is connected in series with a solenoid valve SV57. The function of solenoid valve SV57 is to open the parallel path. when it is deen ergized'. so both valve 265 and valve 263 together regu late the outward flow of air from cylinders I28 and and maintain a normal level of web tension in the festoon and upstream to the unwind. lf solenoid valve SV57 is closed, adjustable restriction valve 263 again becomes the sole means of controlling the descending dancer, and an increase in tension in the festoon results (at least up to the set point of valve 271 which will be described further below). The increase in web tension then results in a greater rate of withdrawal of web from the unwind, slowing the descent of the dancer. Between the above valves and the dancer cylinders is a pressure relief valve 271, which vents to atmosphere at its set point and limits the maximum pressure to which the dancer system may be subjected.

Branch 311 supplies splicer cylinders 226 and 228 via a manually adjustable pressure regulating valve 279 and a pair of two position, four-way solenoid valve SV65 (connected to cylinder 228) and SV66 (connected to cylinder 226).

The A and B unwind stands employ brake cylinders 87a and 87b, respectively. The head ends of these cylinders may be supplied via branches 3170 and 317d (which are seen to be joined to each other) and paired solenoid valves SV36, SV3S, and SV56, SV67. Solenoid valves SV35 and SV36 are energized in alternation thus effecting a switch from brake 87a to 87b or vice versa (by electrical means. further described, below). Solenoid valves SV56 and SV67 are used solely for rapid venting of the brake cylinders 87a and 87b, respectively. Energization of either one results not only in the immediate cutoff of all sources of pressurized braking air to a given cylinder, but also in direct venting to ambient atmosphere of the head end of the cylinder. High pressure braking air may be directed to the various branches or conduits 317a, 317b, 3170 and 3170' (and thence to the brake cylinders) in four different modes, to be described.

The brakes are individually releasable (only when the cylinder heads are vented, as above) due to low pressure air supplied to the rod end of both cylinders 87a and 87b through a common branch 319 which supplies air via manually adjustable, pressure regulating valve 255. This in effect provides a spring" force of low pressure air, always present at the rod ends. The high pressure supplied to the head ends must overcome this. Therefore, a differential braking effect is available for optional use. If the braking effort is found to be too severe, it may be diminished by simply adjusting valve 255 to a slightly higher output pressure, which is applied immediately to the rod ends of the brake cylinders, diminishing the effectiveness of the head-end pressure, regardless of its source.

Branch 313 (MODE l), which is similar to one described by Butler ct al. in US. Pat. No. 3,4l4,208 (column 5, line 67, to column 7, line 9), supplies air to the unwind brake cylinders 87 (a or 1)) via cam 140 which operates pressure regulating valve 144 on the web storage festoon 30. As described above, when dancer 80 is in the lower two-thirds of its travel, the output pressure of valve 144 is at a preset minimum (i.e., producing a low" level of braking of the unwind). When the rising dancer 80 crosses the two-thirds point, and all of the time that it is above that point, the output pressure of valve 144 is higher than it is below the two-thirds point, so that a higher level of braking is applied to the upwind. This tends to decrease web payout from the unwind and to increase web tension. The result is an increased loading on the dancer 80, tending to slow down its rate of rise when it is in the upper third ofits stroke.

Air supplied by branch 313 and pressure regulating valve 144 flows through one side of shuttle valve 304. From there it flows via conduit 329, to solenoid valve SV38 (now energized), and, thereafter. via branch conduits 317!) and 317d and solenoid valve SV39, to solenoid valve SV36 (normally energized) and cylinder 87b.

Branch 315 (MODE ll), which is similar to one described by Butler et al. in US Pat. No. 3,414,208 (column 7, lines 27-43), supplies air to the brake cylinders by means of a manually adjusted pressure regulating valve 312 and solenoid valve SV37 (now energized). lt also supplies air to the other branch of shuttle valve 304, from which the air flows to the brake cylinders via the path described above (MODE l). The output pressure of the manually adjustable pressure regulating valve 312 is set to be higher than the preset minimum pressure" (above, MODE 1) of the valve 144. Therefore, branch 315 0verrides" branch 313, via shuttle valve 304, which opens to conduit 329. It is responsive to whichever of the two branches. 313 or 315, furnishes the higher pressure, and will simultaneously close off the opposite branch to avoid backflow. I

It will be understood that the output of branch 315 is "pulsed, producing only short-duration periodic surges of high pressure at the shuttle valve output. The timing, or frequency, of the pulses is controlled by switch and gears 164, and 166. The duration of the pulses, however, is controlled by time-delay relays, to be described. Pulsing switch 160 is operative only through the lower twothirds of travel of the dancer, being switched into the circuits by means of cam 146 and switch 150 as described in the web storage-dancer section, above. Thus, as the dancer travels upward through the lower two-thirds of its stroke, and the velocity of the dancer is increased, the greater the frequency ofthe pulses to the unwind brake. This raises web tension, at an increasing rate, and slows the rise of the dancer.

In a manner to be described, signals are produced when a running roll of web is near expiration. The first such signal is used to decrease the upwind speed from a high speed to a low speed. This MODE lll operation is accomplished by means of the branch 317, which supplies high pressure air, via manually adjustable pressure regulating valve 331, to a check valve 333 which is connected in parallel with manually adjustable restriction 335. The output of this system is normally blocked by normally energized solenoid valve SV38; the other inlet port of which is being supplied from the conduit 329, as described above. At the time that braking deceleration is demanded, however, solenoid valve SV38 is deenergized for a short period, cutting off all air from the MODE 1 and 11 branches 313 and 315, and supplying air to the brake from the branch 317 (via conduits 317b and 317d, and valves SV39, SV36 and SV67). Branch 317, and associated valve SV38, may also be used for emergency stops by manually deenergizing SV38.

Under the influence of branch 317 the unwind speed decreases toward the 120 fpm level. As the desired speed is reached, (MODE lV) becomes operational and a speed sensor and an electrical control (to be described) energizes solenoid valve SV67, momentarily. This dumps high pressure air from the head of cylinder 87!; and releases the brake. The control also activates branch 321. This branch comprises an amplifying valve AMP-l, the output pressure of which is proportional to pressure input to its pilot. The input to the pilot is supplied by an electrical-pneumatic transducer TRN-l which in turn receives a DC. voltage signal from DC. tachometer 43 on the web storage device. This DC. voltage is proportional to the web speed, and the output air pressure of the transducer TRN-l is proportional to the DC. voltage. The output of the valve AMP-l is connected, via branch 32IA to a normally closed port on the normally deenergized solenoid valve 5V3). When the desired low level of web speed is attained, however, the same electrical control which momentarily deenergized solenoid valve SV67, simulta' neously energizes solenoid valve SV39; thereby cutting off all air from the MODES I. II and Ill (branches 313, 315 and 317}. Air is then supplied to the brake, solely from the low speed control branch 321 via solenoid valve SV39, branch 317d and solenoid valves SV36 and SV67. Unwind web speed is now maintained at the desired low level pending further events.

Branch 323 serves simply to supply pilot air pressure to solenoid valves SV56, SV67, SVS9, SV60, SV61 and SV62, as denoted by the broken line representation. Branch 323 has no control functions of itself.

Branch 325 comprises manually adjustable, pressure regulating valve 299, which supplies air in parallel to solenoid valves SV59 to SV62, inclusive, and to cylinders 157 for driving web clamps I49 (FIG. 6). The A and B sides are substantially identical. thus only the A side pneumatic system will be described. Air is supplied to the head end of cylinder 1570, to effect web "clamping, via solenoid valve SV59', and to the rod end via solenoid valve SV60. This system actuates solenoid valve SV6I), in the clamp open direction, for a short term, followed immediately by deenergization of SV60. This has the effect of not only venting the high pressure air from the rod end of the cylinder, but also of leaving that end open to the ambient atmosphere, thereby permitting high speed drive in the opposite or web clamping direction when this is called for by energizing solenoid valve SV59.

Branch 327 comprises a manually adjustable, pressure regulating valve 301 which supplies air continuously to the web tail detectors [8], previously described.

Sub-branch 3l7e takes pressure regulated air from the output side of valve 331 and supplies it to the upper of the two sets ofinlet ports on valves SV3S and SV36. Solenoid valve SV36 as described above, is normally energized, so the 3l7e branch supply has no effect on the "B" brake. The other valve SV35, however. is deenergized so that air from branch 317a is fed to the brake of the idle unwind A" thereby locking the spindle and keeping it from rotating inadvertently and paying off web to the floor. Manual switches (not shown) permit solenoid valves SV56 or SV67 to be energized to shut off this air, if desired. This permits the idle unwind spindle to be hand-rotated, e.g., to allow the splicer to be hand threaded. After this hand threading, the brake on the idle spindle may be "locked" again.

A balance must be achieved among the various braking elements of the present invention in order to insure proper operation. In the embodiment illustrated, three brakes are used on each side of the unwind means. The running 8 side will be described; however. the A side will be adjusted identically. The three brakes are: the unwind brake 81 and 83 and the hysteresis brakes I43 on the web guiding vacuum rolls 133k and 135/), respectively. The hysteresis brakes 143 are individually adjustable. When imminent web exhaustion from the unwind has been sensed and when the unwind has been decelerated to the low speed level (unwind brake 81 and 83, being under the control of the web speed tachometer 43) transducer TRN! and pneumatic branch 32] will automatically exert just enough braking effort to maintain the low speed, if no other braking effort is supplied. If the hysteresis brake on vacuum roll 135!) is then applied. by electrically energizing the 6 V.I).C. coil means on the brake stator and by manually adjusting the current to the coil by means of a variable resistance (not shown), then the magnitude of the braking effort on the web by the roll [35h may be increased at will, up to a maximum level at which the tension on the web (all web tensions measured between the vacuum roll 1351) and the splicer) is exactly equal to the web tension that would have prevailed if the unwind brake had been the sole means for tensioning the web at the time that web speed was being maintained at the low level, as above. As braking effort exerted by the hysteresis brake on vacuum roll l35h is increased to the point where web tension is higher than that which the automatically controlled unwind brake would have exerted, then such a high level of tension will slow the web excessively or will stop the web completely and no splice will be effected.

On the other hand, if the braking effort of the hysteresis brake on vacuum roll 13511 is set too low (say less than percent of maximum, as defined above) then, when the expiring web tail drops off the core of the unwind there will be an abrupt drop in web tension and a concomitant increase in web speed which may be so great that the web clamp 14912 is incapable of grasping and stopping the web tail. In this event, the tail may be pulled completely through the splicer without a splice being effected. Thus, the hysteresis brake on vacuum roll 135b must be adjusted for I00 percent down to about 70 percent of maximum.

The setting of the hysteresis brake of vacuum roll 13311 is not as critical, since its principal function is to maintain web tension from one vacuum roll I33 to the other, 135, so that the web tail proceeds through the web end detector 181 in an orderly way. For this purpose it is sufficient to adjust the brake on roll 133!) to about 5 to 30 percent of the braking effort exerted by the brake on roll 13517. The sum total of braking effort on rolls [35b and 133!) should not exceed the maximum" as defined above.

ELECTRICAL SYSTEM FIGS. 8a and 8b are electrical diagrams which show the control systems. FIG. 8b is a continuation of FIG. 8a, the vertical lines at the left and right are each continuous electrical conductors energized from a source of V AC energy. The drawing symbols are believed to be conventional; however, the number and letter codes used have meanings as follows. The 500 and 600 series number at the left are line numbers for ease of crference and crossreference.

PB is push button.

CR is control relay.

TD is time delay relay.

i. appearing near contact means that the contacts perform their function instantaneously even though they may be actuated by means of a time delay relay. Thus. not all of the contacts of a given device will function simultaneously.

LS is limit switch.

8V is solenoid valve.

Numbers appearing after a letter designation comprise the reference character for a particular piece of equipment. e.g.. CR52 is control relay number 52.

Numbers separated from the above numbers by a dash uniquely identify a particular contact pair on a given device. c.g., CRSZ-l identifies contact pair number I of control relay 52.

Numbers in parentheses next to a CR or a TD give the number of contact pairs actuated by that CR or TD.

TOAE means timed opening after energizationv TOAD means timed opening after deenergization.

TCAE means timed closing after energization.

TCAD means timed closing after deenergization.

in this description, numbers in parentheses are line numbers in the electrical diagrams (FIG. 8) unless otherwise qualified. It is assumed here that web is being routinely unwound at full speed from the B side of the apparatus. and that the web on the A side is being put in readiness for splicing and running. Regarding the electrical circuits of FIG. 8, it will be understood that in the preceding cycle of events leading up to the running of the B side web. relay CR56 (551) had attained an *unlatched" condition, meaning that the twelve pairs of CRS6 contacts shown in FIGS. 80 and 8b were disposed as follows:

Circuit Contact Effect (cg. for normal" Linc Pair running. B side) (Sol CR56-3 A" Pulse counter off.

(562) CRti-4 B Pulse counter on.

(5h'I.l CRSb-S Circuit open" to SV33. A-- side.

(Still) CRStv-fi Circuit closed" to SV34. B side. cg.

ready to be energized later. to apply vacuum to rolls I333. I358.

(575) CRSfv-l Circuit open"; circuit incapable if initiating A" side functions.

(577) CRSo-Z Circuit closcd": circuit ready to initiate a number of "B" functions. later.

(602) CRSh-J Circuit opcn" to SVM]. SV42. "A" side.

I604) CRSfi-ltl Circuit "closed" to SV48. SVSZ. "B" side.

SV48 energized. activating the web edge position detector to). SVSZ energized. admitting hydraulic fluid to the 8" unwind cylinder 93 so that errors in the 8" web position. if present. are continuously corrected. bringing the running 8" web into edge alignment with a reference plane (not shown).

1st 2) CR56-ll Circuit open" to SV35. A" side.

(bl ll) CRSb-l 2 Circuit closed to SV36. 3" side. putting head end of "B- brake cylinder 87 in communication with SVSR. described further. below.

(6. 2) (R56-7 Circuit "open" to SVSb. A" side. high pressure air "holding A" brake.

(632d) ('RSfi-X Circuit closed" to SVfi7. 8" side. cg.

ready to he energized later to vent head end of B brake cylinder 87.

Four circuits having no dependence on CR56 are also energized initially. viz.:

(691)) None -Continued The tachometer 4] is running at normal web speed having the direct effect of energizing TRl [694); this hitter has the effect ofopening the contacts TRLI (ollit to "make ready" for a later ewnt. to be described. Circuit closcd" to S\'57. having the effect in the pneumatic circuit. of opening the bypass around check valvc Zbl and restriction 26}. thereby permitting web to be withdrawn from the tcstoon 30 at a high rate [if and when demanded. cg. sec below) by permitting air in the dancer cylinders )28 and I30 to escape (to the left in FIG. 7) via restrictions 263 and 265. simultaneously. and then out" to the ambient atmosphere via regulating valve 260,

(694) TRl l [bltil (bill) TDlO l The following then occur. in sequence: 1. The operator threads the A" web end from the unwind over vacuum roll 133a. FIG. 6, under roll [35a up and around the roll 292 (FIG. 5) and up to the web preparation table 270. where the end is held temporar ily by vacuum. The operator next trims the end (e.g.. with a knife) to square it up and applies a strip of doublefaced. pressure sensitive adhesive tape 296 entirely across the web end. He next removes the web from the table 270, moves it rearward or forward. as necessary. to align the rear edge with a fixed reference surface (not shown) aligned with the edge guiding apparatus. He then deposits the web end. adhesive side out. on the roll 232, where it is held by vacuum. The roll is hand rotated to bring the adhesive into confrontation with the opposite roll 230. but separated therefrom. 2. The operator pushes P318 (575) momentarily. signaling the circuits that the above operations are complete and that the new web end A stands in readiness for splicing. Since TD2-2 (575) is normally closed and CR56-2 (577) had previously been closed, pushing PB-l8 completes the circuit to CR53 (577) which closes CR53-2 (578) thus latching-in CR53. CR53-l, 3, 4 and 5 also switch at this time. 3. CR53-l (553) closes. but since TDZ-l (553) is now open. closing of CR53-l only places the CR56 (55!) circuit in a ready" state for eventual switching from B run to A run. 4. CRS3-3 (565) closes. enabling energization of seven circuits (564 to 571) depending from it. but no complete circuit is closed at this time. 5. CR-53-4 (628) closes, but other contacts are open making the (626-628) circuit ready. 6. CR53-5 (645) closes the circuit from the 6V DC. power source to the B hysteresis brakes [43 on vacuum rolls I33 and 135. but CRSS-l (639) is open. thus the D.C. power supply is not on as yet. and the brakes are not energized. 7. Expiring roll B reaches the diameter at which the first preset of the Dynapar pulse counter (560) is triggered. resulting in the closing of the contacts C-l (564). CR53-3 had closed previously. therefore. CRSZ (564) is now energized. resulting in the switching of CRSZ-l. 8. CRSZ-l (567.1) closes. CR56-6 (567.2) had been closed. therefore. SV34 (H6. 6) is energized. resulting in the application of vacuum to both of the B rolls l33b. b, thereby causing the running 8 web to cling to these rolls. 9. Expiring roll B continues to unwind. reaching the diameter at which the second preset of the pulse counter (560) is triggered. This results in the closing of contacts C-2 (566). CR53-3 had closed previously, therefore, CRSS (566) is now energized, resulting in the switching of five contacts, CR55-3, CRSS-l, CRSS-Z, CR55-4, and CRSS-S.

l0. CRS5-3 (617), which is normally closed, is now opened, resulting in the deenergizing of solenoid valve SV38 (FIG. 7). This cuts off any output from the shuttle valve 304, and cuts in pneumatic branch 3171) to 317a. This, in effect, directs high pressure air from pressure regulating valve 331, via branches 3170, 317/). and 317d through previously energized solenoid valve SV36 (SV35 deenergized) to B brake cylinder 87 and immediately starts the web roll B decelerating very abruptly. The velocity of the web entering the festoon 30 now decreases and the dancer assembly 80 starts to descrnd.

l 1. During the period of normal operation, when the web speed was high, tachometer 43 (FIG. 1) generated a high DC. voltage output which was applied directly to TR] (694). As web speed, and thus the DC. voltage, diminish, relay TRl (694) becomes deenergized when the web speed reaches a preselected low level (e.g., 120 fpm). TRl-l (618) now closes, thus completing circuits to TD4 (618) and TDS (619) which, on being energized, switch contacts TD4-1, TD4-2, and TDS-l, respectively.

12. CR55-1 (639) closes, completing a circuit to the 6V D.C. power supply. This furnishes DC. current via CR53-5 (645), previously closed, to the B hysteresis brakes on the vacuum rolls, thus assisting in controlling web tension thereon.

l3. CR5S-4 (626) closes but without effect since CR51-4 has not and will not close in the present cycle, this (626) being a A circuit.

14. CRSS-S (628) closes. This energizes the B webend detector 181, 183, FIG. 6 (CR53-4 having closed previously, Step 5). However, since 13 web is present, nothing happens at this time.

15. TD4-1 (632) closes, completing a circuit via TDS-l (also energized but not open, as yet) and CR56-8, previously closed, to solenoid valve SV67, FIG. 7. Solenoid valve SV67 is thereby actuated, closing off the supply of high pressure air and connecting the head end of the B brake cylinder 87 to exhaust." This dumps the high pressure air in the cylinder, and suddenly releases the B brake, substantially completely, since system volume is low. This dumping occurs in a very short period of time (e.g., 0.1 second) because TDS (619) was previously energized, at the same time as TD4. TDS-l (632) has a "Timed Opening After Energization. It, therefore, opens 0.5 second after being energized, permitting SV67 to return to its former state (e.g.. deenergized, exhaust closed). Ordinarily, this might mean the readmission of high pressure air, except that another circuit and valve change has taken place which will be described.

16. Substantially at the same time that TD4-l (Step was closed, TD4-2 (634) closes, completing a circuit to solenoid valve SV39. This actuates the valve and cuts off high pressure air from pneumatic branch 317b, while opening the valve SV39 to branch 321a. Branch 3210 comprises a source of low pressure air, regulated in proportion to the tachometer 43 output by means of the DC. volt'tige-to-pressure transducer TRN-l, so low pressure regulated air is applied to brake cylinder 87h thereby regulating web payoff from unwind B at the low speed level, e.g., 121) fpm.

17. TD5-2 (619) closes. This shunts TRl-I (618) and maintains the (618) circuit in an energized state. The tachometer 43 (694), by virtue of its low speed and its low DC. output. had previously allowed TR] (618) to close (Step 11). On transfer of the brakes (Step 16) to low-speed control. web speed might increase, momentarily, resulting in a sufficiently high DC. voltage output from tachometer 43 to reopen TRI-I (618). Should this occur, however, it will have no effect because of the closing of shunt circuit, TD5-2 (619). 18. Web payoff from B proceeds. The web tail eventually falls free of the core. The portion of B web extending from roll 133b, (FIG. 6) around 135!) and up to the splicer does not fly about in an uncontrolled manner. however, since vacuum had previously been applied to rolls 133i) and 135]). Furthermore, hysteresis brakes 143 are retarding each of these rolls, thereby maintaining the web in tension. The terminal end of the web proceeds around the top of vacuum roll 133b, finally losing contact therewith, at which time the web end is also drawn through the web end detector 18]. Air being supplied to detector 181 actuates switch 183, in a fraction of a second. This energizes TD7 (628), CR534 having been closed and latched "in earlier (Steps 2 and 5, above) and CR55-5 (628) having been closed (Step 14). The energization of TD7 (628) results in the switching of five contacts TD7-1, TD7-2, TD7-3, TD7-4, and TD7-5.

l9. TD7-2 (628.2) closes, latching-in TD7 (628). The web end detector 181-183, therefore. does not need to hold' TD7. 20. TD7-3 (625) closes, energizing SV61. This admits high pressure air to the head end of clamp cylinder 157b, driving clamp pad 161b into abutment with fixed pad 16512 and seizing the B web therebetween. This stops advance of the B web through the splicer, after a small amount of slippage. At this stage, some twelve to twenty inches of web hang beneath the clamp, and since web feed has stopped altogether, the dancer de scends at an even higher rate than before, to satisfy downstream demand for web. SV57 is open, permitting air to escape at a high rate from dancer cylinders 128 and as explained above. 21. TD7-l (569) closes, energizing TD1 (568) and resulting in the switching of two contacts TD1-1, TD1-2, below. 22. TD7-4 (631), normally closed, is opened instantaneously. TD7-5 (631), in the same circuit, opens, creating no immediate effect but placing the (631) circuit in readiness to actuate SV62 later. 23. TD1-l (569-1) closes, "latching-in" TD-1. 24. TD1-2 (571) closes, energizing TD2 (571) and switching five contacts TD2-1, 2, 3, 4, and 5. 25. TD2-3 (622) closes. Since SPDT LS-36 (622) is on the B side (slotted receiver 245 having been placed on the B side by the operator at the time of A web end preparation), a circuit is completed to SV66 (623), thereby actuating it to admit high pressuure air to the rod end of cylinder 226. This pulls on the crank or eccentric of B roll 230, driving the expired B web over against the standby A web, effecting a splice. Simultaneously, blade 262 is lifted against the B web, into engagement with the slotted receiver, the B web being severed thereby. Meanwhile, A clamp 149 maintains its grip on the now-severed web tail. 26. TD2-4 (638) closes, energizing TD10. TD10-1 (613.1) then closes, energizing SVS'I. This closes the bypass around check valve 261 and restriction 263, in effect increasing the resistance to air flow out of the dancer cylinders [28 and 130. Since web is being consumed downstream of the festoon 30, dancer assembly 80 is still descending because the newly spliced (Step 25, above) wcb roll A has not had time to accelerate as yet. Since the dancer assembly is descending. cylinders I28 and 130 are still expelling air via pressure regulating valve 260. Thus. the effect of closing SV57 is to decrease the rate of expulsion of air from the system, resulting in a pressure rise in the cylinders 128 and 130 and in a marked increase in tension in the festooned web. This tension is propagated upstream to the newly spliced web roll A thereby accelerating it. There is essentially no braking effort on the A roll at this time. As the A roll accelerates. the web meets and eventually exceeds the velocity of web payout. downstream of the festoon. At this point the dancer reserves and the festoon begins to accumulate web.

27. TDZ-l (553) closes substantially simultaneously with TD2-3 (622). above. Since CRSS-l (553) had been closed previously, closing TD2-1 completes a circuit to CR56 (55l). This switches all twelve of the CR56 contacts. For the most part, this has the effect of switching a number of circuits to the reverse of their prior state (e.g.. B to A) or of disabling some circuits until the next splice cycle occurs. Three of the switched circuits are of immediate interest.

"A" side. activating the A" web-edge detector so that errors in web-edge position. if present. are corrected continuously.

28. TDZ-S (560) closes substantially simultaneously with TD2-l (553) and TD2-3 (622), above. The effect of closing TD2-5 is to reset pulse counter (S60). removing" previous counts.

29. TD2-2 (57S) opens. after a delay of about 1.0 second. deenergizing CR53 (577) with the following effects:

Circuit Line Lhange Effect (55]) upen" (RSH-l Opens circuit to CRSb; otherwise without effect since CRSo had switched earlier. Opens "latching circuit for CR5 Opens scvcn dependent circuits. some of which had been opened earlier by other means. c.g.. (564). (567.1]. and (567.2]; the remaining ones are describcd l'iclow Disables web "8" end detector and opens circuit to Tl)? (n28) (sec bclo (565) open (R5334 ((12K) "open" (REE-4 -Continued Circuit Line Change Effect (645) "open" (1253-5 Disconnccts "B" hysteresis brake from power supply. dc energizing hysteresis brakes. 3" rolls.

30. As noted above (item 29) CR53-3 opened; this had the effect:

(568) dcencrgize TDI Opens late-hing" circuit l'Dl-l (569d and opens TDl-Z l57l I to TDZ which itself has five contacts. further described below.

No effect since circuit had been opened earlier.

Places pulse counter in readiness for next cycle.

No effect since no circuit is completed at this time (PB-IR not having been manually actu ated. as yet).

Deenergizes SVofi (623) to admit air to head end of 8" splice cylinder 226. and restore spliccr roll 230 to its "standby" condition.

Deencrgize TDlll (6J8) allowing TDlU-l (blll to "close" after a time delay of about 6.0 seconds. energizing 5V5? (613.1 I thus -opening" the bypass conduit around the control valve (553) "open" TD2l (560) "open" TDZ-S (575 l close" TDZ-Z Circuit Line Change Effect 263. permitting the dancer cylinders l28.l30 to expel air (via valve 260) at a higher rate. once again. if demanded. Described further below. item 3).

(566) decnergize (R55 3l. The effect of deenergizing CRSS (566). above. is as follows:

HM. I83. Opening CRSS-S has no effect on TD7 (628) because latching circuit TD7-2 (628.2) is still closed.

32. When TD4 and TDS were deenergized (above) this had the effects:

(634) open TD4-2 Dcenergize 5V3), disconnecting low-speed brake control, FIG.

7. branch 32la.

"Open" TDS-Z shunt around TR l -l (618). disabling (618) circuit until next cycle.

Two events concerning the brakes occur in quick succession as described below.

(619) "open" TDS-Z "close" TD4-l; energize TDS-l a. Since TDS-l (632) had been open. the deenergiz ation of TDS causes TDS-l to close instantaneously. TD4-l, normally closed (since TD4 had been ener gized). remains closed for a finite time period of about 

1. A method for spLicing the leading end of a standby web to a running expiring web rotatably supported on an unwind means, comprising the steps of: a. providing a running web storage means for maintaining, at a substantially constant value, the speed at which the running web leaves the web storage means when the speed of the running web entering the web storage means changes; b. restraining the running web with a web guide means: c. applying a braking force to the web guide means so that the tension in the running web between the web guide means and the unwind means is almost zero; d. sensing the end of the running web with a web tail sensing means, after it has become disengaged from the unwind means; e. stopping the running web by grasping the running web with a clamp means, after the tail end of the running web has passed through the web tail sensing means; f. effecting a splice between the leading edge of the standby web and the running web, while both webs are stationary; and g. severing the running web.
 2. The method of claim 1 further comprising the step of applying a braking force to the unwind means, when expiration of the running web is imminent, to rapidly decelerate the speed at which the running web enters the storage means from a first high value to an intermediate low value.
 3. The method of claim 2 further comprising the step of maintaining the web speed substantially constant after said intermediate low value of web speed is reached until the web tail is grasped by the clamp means.
 4. The method of claim 2 further comprising instantaneously diminishing the braking force on the unwind means to zero when the intermediate low value of web speed is reached.
 5. In a web supply apparatus of the type comprising: unwind means for supporting a roll of running, expiring web; means for supporting a standby web roll; means to splice the leading end of the standby web to the running web and sever the running web; driving means for the running web; running web storage means; and first running web speed control means to maintain the speed at which the running web enters said storage means at a first predetermined high speed; an improved running web control device comprising: a. web guide means, positioned between said unwind means and said means to splice, to coact with and restrain the running web and to retain the tail of the running web when it becomes disengaged from said unwind means so that the running web is fed evenly to the means to splice; b. web guide braking means comprising a brake to apply a braking force to said web guide means and a web guide brake adjustment means to establish almost zero tension in the running web between the web guide means and the unwind means by adjusting the braking force applied to said web guide means by said brake; c. web clamp means; and d. web tail sensing means for sensing the end of the running web after it has become disengaged from said unwind means, activating said web clamp to grasp the running web and bring the running web to a stop, and energizing said means to splice when the running web has stopped.
 6. The apparatus of claim 3 further comprising a. unwind braking means for applying a braking force to said unwind means and decelerating said unwind means to a second predetermined low speed; b. second running web control means responsive to the quantity of running web on the roll of running web, for actuating said unwind braking means when the quantity of running web on the roll of running web approaches a predetermined quantity and for maintaining said unwind means at the predetermined low speed; and c. means responsive to said second running web control means to activate said web guide braking means when the second predetermined low speed is attained, said web guide braking means being inactive, until said unwind means attains the second predetermined low speed.
 7. The apparatus of claim 4 further comprising means associated with said unwind meAns and said web guide means for aligning the edge of the running web with the edge of the standby web.
 8. The apparatus of claim 4 wherein said web guide means comprises at least two closely spaced web guide rolls, said web tail sensing means is located proximal to said web and between said guide rolls, and said web clamp is located proximal to said web and between said web guide means and said means to splice.
 9. The apparatus of claim 6 wherein said web guide rolls are free running vacuum rolls which coact with said running web by means of a vacuum hold down.
 10. The apparatus of claim 3 wherein said web guide braking means is a hysteresis brake.
 11. The apparatus of claim 4 wherein said second running web control means comprises means to instantaneously deactivate the unwind braking means when the running web enters said storage means at the second predetermined low speed.
 12. The apparatus of claim 4 wherein said web clamp comprises a pair of pads and means to urge said pads together, said pads being resilient pads so that web slippage occurs before the expiring running web stops completely.
 13. In a web supply apparatus of the type comprising: unwind means for supporting a roll of running, expiring web; means for supporting a standby web roll; means to splice the leading end of a standby web to the running web and sever the running web; driving means for the running web; running web storage means; and first running web speed control means to maintain the speed at which the running web enters said storage means at a first predetermined high speed; and improved running web control device comprising: a. unwind braking means for applying a braking force to said unwind means and decelerating said unwind means to a second predetermined low speed; b. second running web control means, responsive to the quantity of running web on the roll of running web, for actuating said unwind braking means when the quantity of running web on the roll of running web approaches a predetermined quantity and for maintaining said unwind means at the second predetermined low speed; c. web guide means comprising at least two web guide rolls, positioned between said unwind means and said means to splice, to coact with and restrain the running web and to retain the tail of the running web when it becomes disengaged from said unwind means; d. web guide braking means comprising a brake for applying a braking force to the web guide means and a web guide brake adjustment means to establish almost zero tension in the running web between the web guide means and the unwind means by adjusting the braking force applied to said web guide means by said brake; e. web clamp means; and f. web tail sensing means for sensing the end of the running web after it has become disengaged from said unwind means, activating said web clamp to grasp the running web and bring the running web to a stop, and energizing said means to splice when the running web has stopped. 